I will try to explain the basics of using Layers and Masks, the basic building blocks within Photoshop. Newbies are often intimidated by Layers and Masks but they really are easy to use in the simplest form and quite powerful once you get your head around what they can do. Iíll start out with a simple Layers example and then go into using masks. Please keep in mind that in the following images Iím demonstrating how I am improving them but rather Iím demonstrating techniques using greatly exaggerated examples. Usually you would use these techniques in a far more subtle fashion. Also, I us a PC so if you use a Mac for all of the keyboard shortcuts I mention replace ctrl with command.

Here I have opened an image of a flower and pressed control Ė j to create a new layer. On the right of the image is the Layers Palette. If you are editing an image and that is hidden go to the menu bar up top select Window-Layers and the Layers Palette will appear. My new layer is labeled as Layer 1, the default name. You can change the name if you want, if I only have one layer besides the original background layer I leave it with the default name. If you are going to be doing something complex with many layers it is a good idea to name the layer with what it does, Iím trying to keep this simple so Iím not going in to that. Letís look at something else here, see the eyeball icon on the left of the layer in the Layer Palette? If the eye is visible the layer is visible in the main editing area. If you click on the eye that image becomes invisible and does not display on the image in the main editing area. Here is an exaggerated example. I darkened the background severely on Layer1, here it is visible.

I may like the background now and that would be the end of the work on this layer but if that is the case why would I bother to use a layer? This is where the power of layers comes in. No matter what I did on that layer, exposure, burn, screen, whatever I can now go back and adjust the opacity of my changes. Look in the upper right of the Layer Palette and there is an opacity slider. In this case I pulled it down to 50%. So now the background is effectively only 1 stop down. Imagine you have many layers open and some of the changes made on one layer make the changes you made on a different layer look like too much. You can go back to the offending layer and back off your changes using the Opacity slider. That is a very powerful tool and worth understanding.

Now Iím done with my layer I have a couple of choices about how to save this. I can save it as a PSD or TIFF file and keep all of the layers. As you can imagine that creates a fairly large file. I tend to not save them in that fashion but there are times when you may choose to do just that. The other method is to save it as a JPG, if you want to do that you canít keep the layers. So then you have to merge them together, no worries thatís easy. I go to the menu and choose Layer-Flatten Image. That combines all the layers together. I then just save the image.

So now let go through a simple example of using Masks. Masks are really a simple concept, think of them as opaque covers. The usual flow is to apply a change, such as linear burn, in a greater degree than you think is necessary. You then use a mask to hide your changes, grab a brush and erase the mask using an opacity less than 100%. This way you can apply subtle controls to the degree of your change. I hope the following will help to illustrate this.
I opened the flower image, hit ctrl-j to create a duplicate layer. I make sure that layer is highlighted and then select just the flower. I then go the dropdown at the top of the Layers Palette and select Linear Burn.

That works fine if I want to apply the same level of burn to the whole image but if I want to be more selective I can use a mask. Iíll go back to the 100% burn image. Then I go to menu Layer-Layer Mask-Hide All.

I want to remove some of the mask in order to unhide the burn. So I hit B to give me a brush. I then right click the image and the brush selection menu comes up. I choose a soft round brush, fifth in the top row shown. If the diameter isnít what you want us the [ key to make it smaller and the ] key to make is larger. Yes there are other shortcuts but Iím keeping this simple so I wonít confuse things with more options. You also want the brush to be white not black. Look in the toolbar menu on the left of the image below. On the bottom you'll see an icon that is a black square and a white square. Hit X until the white square is on top.

The brush by default is 100% opacity and flow; look at the top of editor under the menu bar is the tool details bar. In this case it is telling me that the brush mode is normal, the opacity is 100% and I have backed the flow down to 46%. Think of flow like water in a hose. You can get things just as wet with a low flow as high flow, it just takes longer. We usually want to do things subtly as opposed to grossly when editing. So I chose 46%, if I brush it once I remove 46% of the mask. If I hit it again I remove 46% more, this gives me lots of control.

I highlighted the area that I brushed in the image below. If you look carefully you can see subtle differences in the level of burn within the dotted lines. Now if I thought this was too much remember I could go to the layers opacity slider like I did above and lessen the amount of change.

I hope this simplifies the use of these tools. They can be used in a myriad of ways allowing an amazing degree of control of how you tune your images. As always feel free to ask questions or add thoughts of your own.

Nice tutorial Tim! On the mask, does it matter what color your brush is when painting with it? I know when I copy and paste an image into a layer, I can use a black or white brush to reveal or hide the underlying layer. Wondering if the same is true with the masks.....